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Condition of cam and rockers for 1275
Posted: Thu Mar 31, 2016 10:10 pm
by bluegrass
Hi.
I'm sorting through some parts ready for when i start putting together a midget 1275 engine.
I have an mg metro cam which has some wear (A burr on a couple of edges) and i'm not sure if i need to have it machined in some way or if its ok.
Here is a pic that shows the area i am talking about.
I also enclose a photo of the rockers (metro) which again have some wear.
Thanks for any advice.[frame]

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Re: Condition of cam and rockers for 1275
Posted: Thu Mar 31, 2016 10:18 pm
by les
You might be able to stone the rockers to get an even surface but you may be wearing through the case hardening, something that looks like has already happened to the cam lobes, if it was mine it would be in the bin.
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 7:24 am
by philthehill
I have to agree with Les - both the cam and the rockers are only fit for the scrap bin. You may be able to salvage the rocker shaft, pillars and spacer springs.
In relation to the camshaft what are the cam followers like especially the contact face between camshaft and follower?
Phil
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 8:07 am
by bluegrass
Thanks for your thoughts, very much appreciated.
To achieve a good outcome with the cam , I just contacted AC Dodd who sells re-ground cams of high regard in the mini world. Roy ('bmcecosse') has mentioned him a few times on the forum. He will accept this cam as a surcharge against one of his as it is fine for his purposes of re-grinding. The surcharge would have been more than i paid for this one, so that works out well.
The rockers i will return as not suitable for purpose.....I just bought them on ebay.
I'll be more careful when i look for another set....
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 12:02 pm
by bmcecosse
The picture of your rockers demonstrates well the terrible 'offset' geometry where the rocker acts off-centre on the valve tip. Far better to get a set of the pressed steel rockers - and spend some time aligning them perfectly over the valves. The cam wouldn't have worried me - looks like it has probably been there from 'new' and could have just been smoothed off. New cam followers are a 'must'. Are you going for the RS cam from ACD ? Would very much like to hear how you get on with it !
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 12:27 pm
by bluegrass
Hi Roy.
I think i can re-use the rockers on the midget engine with big valve head, but on the 1098 with standard valve 940 head , will the 1098 rockers (adjusted) be ok or should i look out for 1275 ones?
I spoke to Adrian and he wasnt worried about my cam.....thought it a good candidate for his needs. He recommended the 'Rt' cam for my intended set-up.....1275 / big valve head/ hif44, but its not 100% decided yet. He needs to receive my cam and make sure it's ok as a trade in. I could go Rs.....what do you think. Here are his cam descriptions.[frame]

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Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 1:52 pm
by bmcecosse
Well - it's the RS cam they all rave about in their Minis - but of course a lighter car and often enthusiastically driven! I have to say - that's what I would be choosing. The RT looks hardly any different to the standard cam - just a bit more lift. I didn't appreciate he was looking for cams - I binned a few just a couple of weeks ago - ones which would probably have made good 'regrind' bases. He sells both 'regrind' and 'billet' versions of his cam profiles. They seem to be provided by Newman cams.
http://www.newman-cams.co.uk/ Perhaps you could ask them for an opinion on what will suit best?
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 2:21 pm
by bluegrass
He requested a cam in exchange otherwise a £50 surcharge....Yes i do agree that the RT does look 'mild', and the devil in me thinks why not go for the RS. Maybe he saw the words Morris Minor and thought he should play it safe, though i did tell him the engine spec......I do have a few days to think about it...I only just sent mine to him and then he contacts me with billing.
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 2:22 pm
by les
If you thought that cam wouldn't worry you Roy, I'd hate to see one that would!

Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 3:40 pm
by philthehill
If the cam can be salvaged as a regrind all well and good.
Where the burr is located - the rubbing surface of the cam does not appear to be parallel to the centre line of the cam which it obviously should be. If the rubbing surface is not parallel it may be that the cam follower has caused the burr. If you have the cam follower which sat on that particular lode - a photo of the bottom of that cam follower would be appreciated.
I am still of the opinion that the surface hardening of the cam lobe has been broken through and the soft metal underneath the hardening is what has formed the burr.
With a reground cam I would always ask the question 'Has the cam been re-hardened after the profile re-grind' ?
Phil
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 3:41 pm
by liammonty
AC Dodd knows what he's talking about - I would take his advice regardless of whether people think it looks 'wild' enough or not. The RT is a vast improvement over the original in my engine and indeed the MG Metro cam I had in it briefly (granted the engine is different spec to yours). Remember that there has been a shift from overall duration to lift and ramp in order to improve cam performance these days - looking at the overall duration it looks very ordinary, but the duration doesn't tell the whole story. Also consider how much time you spend at over 5000 RPM, and whether you fancy losing the already fairly low bottom-end torque that your engine has to gain a bit more poke at 6000 RPM.
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 3:45 pm
by bmcecosse
There's no damage I can see on the working surface of the lobe itself - just a chip at the side, and as I suggest - probably been there from new. The early cams were only 3/8" wide after all. It would be fine with any rough edge stoned off. Wouldn't worry me in the least. If it was a 'full race' engine with full race timings /high lift /high force valve springs etc etc - then yes - it would concern me then. Just to confirm 'bluegrass' - this is for a 1275 engine - yes? A 'high lift' cam is no use (and not necessary anyway) on a 1098 with 940 head...
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 3:47 pm
by bmcecosse
If I was to say 'white' -Liam would say 'black'.

That's becoming more and obvious every time I post. If all you want is more lift - then just use the (horrible in my view) high ratio rocker kit! From what I have seen of the RS cam power curves - it's a very flat low/mid range high torque cam. Hardly worth the money for the small increase of the RT cam - just my opinion, and I would definitely go for the RS.
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 5:31 pm
by liammonty
bmcecosse wrote:If I was to say 'white' -Liam would say 'black'.

That's becoming more and obvious every time I post. If all you want is more lift - then just use the (horrible in my view) high ratio rocker kit! From what I have seen of the RS cam power curves - it's a very flat low/mid range high torque cam. Hardly worth the money for the small increase of the RT cam - just my opinion, and I would definitely go for the RS.
I don't post to either agree with you or disagree with you, BMC. I post if I have an opinion, based on experience, to offer advice to people. It doesn't necessarily mean it's right (we are all wrong sometimes!), but it's my opinion based on experience. Hence this post - I have fitted that cam to my engine, and know the effect it has had, so I offered an opinion based on experience. If from time to time that is different to your opinion and it offends you, that's unfortunate. You aren't afraid to disagree with people if you think it's appropriate, and nor am I. And I take it it's not personal when you do it, so why should it be if I do?
Keep smiling

Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 5:35 pm
by bmcecosse
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 5:45 pm
by bluegrass
Its all a bit of fun at the end of the day....none of it is really about right or wrong, just different ideas. I do appreciate hearing the different opinions and whatever cam goes in between those two mentioned, it will still be ok. it will certainly go better than the 1098 already in

I'll talk to Adrian some more and see what he thinks. I also forgot to mention that this car will be pulling a 3.7 diff and have a midget 1275 box fitted if that makes any difference.
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 6:26 pm
by les
Exactly, I can't imagine what cam Roy is looking at, to be probably like it since new but I'm sure we won't fall out over the disagreement. In fact we may do a Specsavers ad together!

Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 6:37 pm
by bmcecosse
Hang on - if this ACD cam is for a 1098 engine IT'S TOO HIGH LIFT !! That's the beauty of the MG Metro cam - the lift is same as before - so ideal for the 1098 conversion with 940 head. The extra lift on that ACD cam is fine on a 1275 - but on a 1098 you would need to sink the valves an enormous amount to get clearance. Or end up with some combination of valve sinking AND block pocketing. Not wise I suggest. Stick with the MG Metro cam - let's see some better pictures of the 'damaged' lobe.
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 6:41 pm
by bluegrass
Hi Roy, no, the AC Dodd cam we are talking about here is for a 1275 midget engine with big valve 940 head and hif44, running a 3.7 diff and midget box.
The mg metro cam is on its way to Adrian as we speak, so no more pics of that I'm afraid.
I do have another Morris which we have spoken about before which has a good 1098 engine. I intend to do your 'classic ' 1098 conversion to that, probably keeping its original cam, and getting an hif38, standard valve 940 head, mg metro inlet manifold with standard exhaust. Again, running another 3.7 dif.
Re: Condition of cam and rockers for 1275
Posted: Fri Apr 01, 2016 7:44 pm
by bmcecosse
Phewwww - ok -all that will work well then. Keep us informed of progress please!